Background of the Invention

The present invention relates to a cremator, which may be referred to as an incinerator, for cremating human or animal bodies. Normally, a cremator has a cremating chamber, an opening for loading a body into the chamber, heating means, means for supplying combustion air to the cremating chamber, and means for permitting combustion gases to escape.

A particular problem exists when disposing of animal carcasses. I.t is time-consuming and difficult to bury the carcasses, and sometimes burial does not comply with health regulations; it is likewise time-consuming and often difficult to transport the carcasses to a central crematorium or other establishment for disposing of the carcasses. Very rarely, such problems can occur with human bodies, if there is a major disaster.

The invention also relates more generally to the design of cremators.

The Invention

According to a first aspect of the invention, there is provided a readily transportable cremator for cremating bodies.

The cremator may for instance have lifting points so that it can be lifted by a standard skip transporter or container transporter. Alternatively, the cremator can be mounted on a demountable pad or unit, a trailer or a lorry. The cremator may be transportable by a fork-lift ^■ truck. More generally, the cremator can be of light weight so that it is transportable in any suitable way.

Preferably the cremator has a cremating chamber and an ash pit of generally hexagonal and vertical section with the top and bottom horizontal and the other sides inclined.

The inclined sides help to bring gases towards the top of the cremating chamber above the carcass. In this manner, the heat is concentrated above the carcass. The hexagonal section may also provide good flow of gases along the top of the cremating chamber towards ducts for removal of combustion gases. The structure is simple and allows a good flow of combustion gases without complicated structures.

The cremator may also comprise a duct passing along the sides of the ash pit for incoming combustion air.

Preferably, the cremator comprises a cremating chamber including a grate for supporting a body to be cremated and an ash pit below the grate, burner means being provided for fluid fuel in the ash pit below the grate.

Means for feeding additional combustion air may also be provided in the ash pit.

According to a second aspect of the invention, there is provided a cremator for cremating bodies, having a loading member movable between a lower position in which a body can be placed on the loading member and a raised position, wherein on lifting the loading member from the lower position to the raised position, the body is loaded into the cremator.

When open, a platform portion of the loading member can lie on the ground or adjacent thereto, and can have a horizontal surface for receiving the body. In this way, it is relatively easy to load the body into the cremator as the body can merely be placed on or rolled onto the platform. Any suitable mechanism can be used for lifting the loading member, for instance a manually operated screw or one or two hydraulic rams. The door can be hinged, e. g. at about mid-height of the cremating

chamber.

Preferably, there is a loading opening which is closed by a separate sealing door. The sealing door may be pivotally mounted on the top of the cremator. Preferably, the sealing door is arranged to pivotally close the loading opening with the loading member closable over the sealing door. Having the sealing door separate from the loading member allows the latter to be made of heavy gauge steel. If such a structure is directly in. contact with the heat of the furnace, problems of expansion and distortion can arise.

Preferably stop means is provided adjacent the loading opening and projecting above the level of the pivot of the loading member. This can provide a ledge against which an animal carcass will rest briefly while the loading member is being raised. As a result, the carcass will be tipped or rolled directly onto the grate. If a stop means is not present, the carcass can slide too quickly onto the grate and may damage it. Preferably, the stop means is pivotally mounted with respect to the loading opening. Preferably, the stop means is pivotally mounted with respect to the loading member. The stop means can be mounted to rotate between a first position in which it projects above the level of the pivot of the loading member and a second position in which it lies flat against the loading member so that

the loading member can be folded neatly against the sealing door.

According to a third aspect of the invention, there is provided a method of operating a cremator of the type comprising a cremating chamber including a grate for supporting a body to be cremated, an ash pit below the grate and gas burner means in the ash pit, comprising feeding a fuel rich mixture of gas and air to the gas burner means.

It has been found, surprisingly, that the most efficient way to burn a carcass in the cremating chamber is to envelope it in a fuel rich flame, rather than an air-rich flame. Preferably, further combustion air required to completely burn the carcass is supplied to the cremating chamber adjacent the burner means in the ash pit.

According to a fourth aspect of the invention, there is provided a cremator for cremating bodies, comprising a cremating chamber including a hearth for supporting a body to be cremated and an ash pit below the hearth, ducts being provided passing along the ash pit, for supplying combustion air to the cremating chamber.

The design of the cremator may be fairly compact and the combustion air supplied to the cremating chamber is

effectively pre-heated. Furthermore, the slight cooling effect of the incoming air is restricted to the lower part of the cremating chamber, rather than the upper part, so that the complete combustion is not interfered with.

According to a fifth aspect of the invention, there is provided a cremator for cremating bodies having a cremating chamber which communicates via an opening with a duct for removing combustion gases from the cremating chamber, the highest part of the opening being below the top of the cremating chamber.

Having the opening below the highest point of the cremating chamber allows hot gases to be concentrated at the top of the cremating chamber. This keeps the temperature in the cremating chamber at a high level. The temperature at the top is generally in the region of 850 to 900'C.

According to a sixth aspect of the invention, there is provided a cremator having a cremating chamber, wherein the walls of the cremating chamber comprise, in succession from the cremating chamber outwards, a stainless steel wall, a wall of insulating material, and a structural steel wall.

The sixth aspect of the invention allows a simple,

strong wall to be constructed. The stainless steel protects the insulating material from hot fat, which could otherwise degrade it. In this manner, a relatively light insulating material (for example, the material known as Newtherm 1000) may be used instead of, for example, firebrick. Firebrick is unsuitable because it becomes brittle in use and is unsuitable for transportation. The outer structural steel wall is protected from the heat by the insulating material so that problems of differential expansion warping the cremator may be avoided.

According to a further aspect of the invention, there is provided a cremator for cremating bodies, comprising a cremating chamber including a grate for supporting a body to be cremated, an ash pit below the grate, a duct for combustion gases which duct passes around the ash pit, and means for causing the combustion gases to pass down into the ash pit and around the combustion gases duct before exiting from the cremator.

The combustion gases can pass around three sides or four sides of the ash pit, and thus maintain a high temperature in the ash pit for causing combustion of solids and volatile gases.

The means for causing the combustion gases to pass down into the ash pit can include at least one blower for blowing combustion air into the cremating chamber and/or

at least one exhaust fan for drawing off combustion gases. The arrangement is preferably such that the combustion air passes into the cremating chamber through ducts or nozzles which are inclined, being directed towards the centre of the cremating chamber and towards one end of the cremating chamber, the combustion gases duct being connected to the end of the ash pit oppositethe end towards which the combustion air gases are directed. In this way, a through current is created in the cremating chamber and while a current is created in the ash pit in the opposite direction to that in the cremating chamber, there is a tendency for the hottest gases to rise through the hearth and for somewhat cooler gases to be drawn off.

According to a further aspect of the invention, there is provided a cremator for cremating bodies, comprising a cremating chamber including a hearth for supporting a body to be cremated, an ash pit below the hearth, means for supplying combustion air to the cremating chamber such that the combustion air is directed to one end of the cremating chamber, as seen in plan, and a duct for combustion gases at the opposite end of the ash pit so that the combustion gases leave the ash pit at the end opposite to which the combustion air is directed.

According to a further aspect of the invention, there is provided a cremator having a cremating chamber and ash

pit of generally hexagonal vertical section with the top and bottom horizontal and the other sides inclined, the ash pit being provided in the bottom part, ducts for gases passing along and outside the inclined sides of the hexagonal section.

The hexagonal section provides a convenient form of cremating chamber and ash pit. Particularly for ready transportation in accordance with the first aspect of the invention, the hexagonal section can be enclosed by an outer housing of rectangular vertical section, and the top and bottom of the hexagon can form part of the top and bottom of the housing. The loading opening can be in one side of the cremating chamber and a lift-up door can be provided in accordance with the second aspect of the invention, the door being hinged about an axis parallel to the axis of the cremating chamber and the door itself forming part or all of two sides of the hexagon, the portion of the door which is hinged to the remainder of the cremator forming part or all of one side and the remote portion of the door forming part or all of another side which will be substantially horizontal when the door is open.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic isometric view of a first embodiment of the cremator;

Figure 2 is a vertical cross-section of the cremator of Figure 1;

Figure 2a is a detailed section of the cremator wall;

Figure 3 shows an end view of the cremator of Figure 1, when the sealing door is closed;

Figure 4 shows a detail of the stop bar pivotally mounted on the loading member;

Figure 5 is a perspective view of the burner arrangement of the first embodiment;

Figure 6 is a horizontal section of the cremator of Figure 2 along the line VI-VI;

Figure 7 is a schematic perspective view of a second embodiment of the cremator, in vertical cross-section along the line VII-VII in Figure 8;

Figure 8 is a schematic horizontal section through the cremator of Figure 7, along the line VIII-VIII in Figure 7;

Figure 9 is a schematic horizontal section through the cremator of Figure 7, along the line IX-IX in Figure 7; and

Figure 10 is a schematic vertical, longitudinal section through the cremator of Figure 7, along the line X-X in Figures 7, 8 and 9.

The cremator 1 shown in Figures 1 to 6 has a single housing 2 of a similar size to a skip, for instance about 2 metres wide, 3 metres long and 2 metres high, and is sufficiently strong for lifting. The cremator 1 can be lifted by a normal skip lorry and is readily transportable. Lifting, points (not shown) may be provided on the cremator 1.

The housing 2 comprises a cremating chamber 3 and ash pit 4 of hexagonal section with two parallel sides (the top and bottom) horizontal, the other sides being equal and about 1.5 times the length of the top and bottom. The cremating chamber and the ashpit are separated by a grate 5.

As shown in Figure 2A, which is a large scale section of the housing 2, there is an outer shell of sheet steel S which may be 3 to 5 mm thick. This layer of steel S is the structural part and gives the body strength. On the inside of the steel, and protecting it from the extreme

heat inside the cremating chamber there is a layer of insulating material I. On the inside of the insulating material I, there is a layer of stainless steel ST, which is thin. The stainless steel protects the insulating material from liquid fat produced by heating the carcass which would otherwise degrade the insulating material.

The cremating chamber 3 has an upper loading opening which is closed by a sealing door 6. The sealing door 6 extends the whole length of the cremating chamber 3 and is pivotally mounted about a generally horizontal axis 7 about half way along the width of the top side 8. The sealing door 6 is shaped so that it closes the open part of the top side 8 and one of the upper sloping sides. The sealing door 6 is suitably provided with insulating material which is not shown in the Figures.

A loading member 9 is provided, which extends the whole length of the cremating chamber 3 and is pivotally mounted about a generally horizontal axis mounted at the junction of the upper and lower sloping sides on one side of the cremating chamber 3. The loading member 9 comprises a rigidly constructed grid for bearing the weight of a carcass. In the open position, as shown in Figures 1 and 2, a first portion 10 of the loading member 9 lies flat on the ground and provides a horizontal surface for receiving an animal carcass. The

loading member 9 is preferably actuated by a hand operated screw device, which allows fine control of the position. Hydraulic rams may be used to raise the platform, but this requires additional auxiliary power equipment. Once an animal carcass has been placed or rolled onto the portion 10, the loading member 9 is lifted up and the animal carcass is dropped or tipped onto the grate 5. A stop means comprising a bar 11 is shown pivotally mounted on the loading member 9 and its operation will be described further below. The loading member 9 can be closed over the sealing door to lie neatly against the outside of the cremating chamber, as shown in Figure 3.

Heat for burning the carcass is provided by a fluid fuel, such as gas or oil. The fuel may be stored in tanks or pressure vessels mounted on the cremator 1 (not shown). As described further below, a fuel rich mixture of fuel and air is delivered along the pipe 12 (controlled by stopcock 13) to burners 14 located in the ash pit 4 beneath the grate 5.

A fuel rich (yellow) flame is produced which envelopes the carcass. The further combustion air required to burn the carcass is delivered into the ash pit 4 alongside the burners 14 by pipes 15. The pipes 15 are connected to ducts 16 which extend along the lower

sloping sides of the cremating chamber 3 and ash pit 4, whereby the air fed into the ash pit is pre-heated to a certain extent. As the burners are located beneath the carcass, the natural convection of the hot products of combustion is used to bring them into contact with the carcass.

The products of combustion flow up from the carcass to the upper part of the cremating chamber 3 and exit via a pair of ports 17 located in the end hexagonal walls of the cremator 1. The ports 17 are located a little below the top of the cremating chamber 3. This ensures that an upper layer of very hot gas is collected in the upper part of the cremating chamber 3 which helps to retain the temperature at high level in the cremating chamber 3.

In operation, the cremator may be pre-heated electrically or by burning fuel in the cremating chamber to bring the cremator 1, particularly the combustion chambers 18, up to operating temperature. In cremating bodies, a major problem is to dispose of the water content. Bodies comprise over 70% of water and this has to be driven off as steam. In the optimum mode of operation, the temperature is maintained fairly high, but not too high. In the first part of the operation, the water is driven off as water vapour before substantial combustion occurs.

The combustion gases are led from the cremating chamber 3 through combustion chambers 18, which lie adjacent the upper sloping faces of the cremating chamber 3 so that the gases are maintained at high temperature to allow further combustion of combustion products. The resulting gases are then drawn out of the chimney 19.

In operation, the temperature inside the cremating chamber is different at different heights. However, the temperature in the upper part of the cremating chamber may be in the region of 850 to 900'C.

The inclined sides of the cremating chamber help to concentrate the hottest gases directly above the carcass and may help to improve the flow out of the ports 17.

If the chimney 19 is made large enough, the whole device can be operated by natural draught. It is preferable that the draught is not too fierce so that the residence time of combustion gases in the combustion chambers 18 and the cremating chamber 3 is long enough to allow complete combustion to occur. A damper (not illustrated) may be provided in chimney 19. The combustion air is preferably drawn through the ducts 16 by natural convection through the cremating chamber 3 and by the Bernoulli effect in the region of the fuel jets. Auxiliary fans or air forcing machines may be

provided, but these increase the complexity of the device and require auxiliary power units.

Figure 4 shows the two extreme positions 11 and 11' of a stop bar 11 pivotally mounted on loading member 9. Pivotting platform 9 is itself pivotally mounted on the cremator 1 at 20. The stop bar 11 operates in the following manner. The stop bar 11 is freely movable between a first and second position on pivotting platform 9. When the loading member 9 is stored or lowered to the ground, the stop bar 11 lies in a first position substantially flat against it. A carcass is then placed upon loading member 9 and the latter is then raised. The stop bar 11 will fall into its second position 11' when the loading member 9 has reached a certain height. As the carcass starts to slide down the part 21 of the loading member 9, it is held by stop bar 11. Stop bar 11 is of such a size that when the loading platform has reached a given further height, the carcass will readily tumble over it. The stop bar 11 serves to prevent the carcass sliding onto the grate 5 at an oblique angle and hitting the far sloping sides of the cremating chamber 3 and damaging them. With the stop member, the carcass falls or rolls neatly onto the grate 5.

Figure 5 shows a detail of the burner and auxiliary air system, which is located in ash pit 4. A fuel rich

air/fuel mixture is delivered along pipe 12 to burners 14 which are arranged in the top of pipe 12. The positioning of the burners 14 is important. It is important to ensure that all of the carcass burns at substantially the same rate, otherwise a large hole may be formed on the grate 5 through which all the hot gas passes without burning the carcass.

It is found that a cow carcass, for example, has much more matter at the leg and shoulder parts and less in the middle and burns relatively slowly at the ends. Accordingly, burners 14 should be mounted more closely at the ends than in the middle of the pipe 12.

It is found, surprisingly, that the most efficient way of burning a carcass is to envelope it in a large, relatively slow moving fuel rich flame. Accordingly, the air/fuel mixture fed to the burners 14 is relatively rich in fuel. When gas fuel such as propane is used, this gives rise to a yellow flame rather than a blue "Bunsen" type of flame.

As the mixture supplied to the burners is deficient in air, further combustion air must be supplied. This passes in to the ash pit 4 through tubes 15, having been pre-heated in ducts 16 as described above. The tubes 15 comprise planed ends 22 which give the outcoming air an upwards velocity, to ensure a smoother flow of air over

the carcass. The ends 22 are preferably located at positions along pipe 12 between burners 14 rather than adjacent them.

Figure 6 shows a horizontal section along line VI-VI of Figure 2. The loading member 9 is shown in some detail, along with the stop bar 11.

Also shown are the paths of combustion gases from the cremating chamber 3, along combustion chambers 18 to chimney 19.

The cremator shown in Figures 1 to 6 may be enclosed on all non-opening sides with insulating material to improve the heat retention properties. The sealing door 6 will be insulated as well. The external shape of the insulated cremator may of course be substantially rectangular to provide a smooth sided structure. The cremator 1 may be fixed to or contained within a framework of heavy gauge steel structural members (not shown) to provide the strength for transporting the cremator.

The cremator shown in Figure 7 has a single housing 23, which may also be of size similar to a skip. It will be sufficiently strong for lifting, lifting points 24 being shown in Figure 10 and their positions being indicated in Figures 8 and 9. The cremator can be lifted by a

normal skip lorry and is, again, readily transportable.

The housing 23 contains a cremating chamber 25 and ash pit 26 of hexagonal section with two parallel sides (the top and bottom) horizontal, the other sides being equal and about 1.5 times the length of the top and bottom. The cremating chamber and the ash pit are separated by a grate or hearth 27. The cremating chamber 25 has an upper loading opening which is closed and sealed by a lift-up door 28 which extends for the whole length of the cremating chamber 25 (as indicated in dashed lines in Figure 8) and is hinged to the housing 23 along a horizontal axis at about mid-height of the cremating chamber 25 and ash pit 26. The portion of the door 28 which is hinged to the remainder of the cremator forms one side 29 of the hexagon and the remote portion forms another side (the top) 30. In the open position, as shown in Figure 7, the door portion 30 lies flat on the ground and provides a horizontal surface for receiving an animal carcass. The door 28 is actuated by two hydraulic rams or a manually operated screw (not shown), one ^' on each side of the door 28, and once an animal carcass has been placed or rolled onto the portion 30, the door 28 is lifted up and the animal carcass is dropped or tipped onto the hearth 27.

In order to provide combustion air, there is a main air blower 31 which draws air in from an inlet and passes it

through a transverse duct (or plenum) 32 into triangular-shaped ducts 33 (see Figures 7 and 8) outside the upper inclined walls of the cremating chamber 25, the ducts 33 acting as plenum chambers; when the door 28 closes, a hole (not shown) in the door 28 registers with a hole (not shown) in the end of the transverse duct 32 to provide a combustion air connection. In this way, there is some pre-heating of the combustion air by the end of the cremating chamber 25, by the upper inclined walls, and by the wall of the transverse duct 33; the respective surfaces can be finned to improve the heat interchange. Fuel nozzles 34 (see Figures 8 and 10) with coaxial combustion air ducts are provided along the cremating chamber 25 and directed downwards towards the hearth 27 and inclined towards the left-hand end; there are also fuel nozzles 34 in the door 28, connected by a flexible hose (not shown) to the fuel supply. The combustion air enters the cremating chamber 25 around the fuel nozzles 34. The fuel supply can be gas or pressurised liquid, storage cylinders 35 being indicated.

The arrangement is such that the animal carcass (or body) is heated as quickly as possible to its maximum temperature, which may be 900 to 1100 ^* C, and the air pressure can be adjusted to obtain complete combustion, for instance by adjusting the speed of the blower 31 or by adjusting a valve flap (not shown) downstream of the

blower 31. Once the animal carcass has begun to burn, it creates its own fuel to a certain extent. The combustion gases pass down into the ash pit 26 and out of the right-hand end of the ash pit 26 into a combustion gas duct 36 which passes right round the ash pit 26, passing transversely across the right-hand end, down one triangular-shaped duct, transversely across the left-hand end and back along another triangular-shaped duct. The combustion gases then enter the bottom of an exhaust flue 37 and are drawn up the flue by an exhaust fan 38 (see Figure 8) which is near the top of the flue 37 and is carried on the same shaft as the blower 31. The blower 31 and the exhaust fan 38 can be driven by any suitable driving means, for instance an electric motor 39, a hydraulic motor or a belt-driven pulley. The length of the exhaust duct 36 and flue 37 is about 10 metres.

The tendency is for the combustion gases to be directed towards the left-hand end of the hearth 27 so that they and the hottest gases rise up through the hearth 27 while somewhat cooler gases pass out of the right end of the ash pit 26. In this way, the combustion gases swirl over the carcass, are drawn through the ash pit 26 in generally the opposite direction to movement in the cremating chamber 25 and remain at combustion temperature so as to burn off solids and volatile liquids, and are drawn up the flue 37 for discharge to

the atmosphere.

A diesel or petrol engine 38 (Figure 10) provides hydraulic power e. g. for the door rams and if required generates electrical power for the blower 31 and exhaust fan 38.

The top and bottom of the cremating chamber 25 and the outer wall of the exhaust duct 36 are heat insulated so that the outside of the housing remains, cool.

The above invention has been described above purely by way of example, and modifications can be made within the spirit of the invention.